import numpy as np
np.random.seed(0)
(n, m) = (10, 20)
edges = [(0, 1), (0, 2), (0, 3), (1, 2), (1, 3), (1, 5), \
         (2, 4), (2, 5), (3, 5), (3, 6), (4, 6), (4, 7), \
         (5, 6), (5, 7), (6, 7), (6, 8), (6, 9), (7, 8), \
         (7, 9), (8, 9)]
a = 2*np.random.rand(m, 1)
x_max = 1+np.random.rand(m, 1)
B = m/2.0
